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If you've ever wished to create your own wireless streaming amp modules...

somebodyelse

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It seems a viable alternative to the Hifiberry miniamp I've been using with picoreplayer. I wish they had some more realistic power output claims - 2x40W 'peak power' from a 5V 2.5A power supply that also has to power the Pi?!

Somewhat related - how will you keep a pair in sync wirelessly well enough for stereo? LMS is up to the job for multi-room, but I don't think it's up to stereo. PTP apparently doesn't deal well with the variable latency on WiFi. gstreamer's old time sync apparently copes much better, and might be good enough, but I've not tried it.
 
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BillG

BillG

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I wish they had some more realistic power output claims - 2x40W 'peak power' from a 5V 2.5A power supply that also has to power the Pi?!

Apparently you've never heard of voltage boosters/step up converters. If you read the literature it actually mentions one... :rolleyes:
 

Berwhale

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Apparently you've never heard of voltage boosters/step up converters. If you read the literature it actually mentions one... :rolleyes:

Don't voltage boosters lower the current? So wouldn't the P in P=VI stay the same? Are you suggesting that you can get more power out of a system than you put in? Or am I missing something regarding how 'music' power is calculated as opposed to electrical power?
 
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BillG

BillG

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Don't voltage boosters lower the current? So wouldn't the P in P=VI stay the same? Are you suggesting that you can get more power out of a system than you put in? Or am I missing something regarding how 'music' power is calculated as opposed to electrical power?

Nah, you're just typically offensive as opposed to helpful. That's a common trait around here unfortunately... :p
 

Berwhale

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I don't think i'm the one being offensive here, I just asked some reasonable questions. My understanding is that Power (P) = Voltage (V) x Current (I) which is an equation derived from Ohm's Law. 5V x 2.5A = 12.5W, so how can the amp output 2 x 40W?
 

somebodyelse

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Apparently you've never heard of voltage boosters/step up converters. If you read the literature it actually mentions one... :rolleyes:
Perhaps I should have been more explicit - even by the usual standards of 'peak music power' type claims, 80W output for <12.5W continuous power input is excessive. If they included another set of screw terminals for a higher current 5V supply they might have a decent claim, but they don't. While the FCC power rating methodology is unrealistic in one direction, it's claims like this that made it necessary in the first place. Perhaps it's the journalist conflating the chip maximum capabilities and those of its implementation on the Pi hat, or the text was meant to refer only to the chipset despite it being placed between a headline about the Pi hat and a photo of it, and I'm overly sensitive to the increasingly common practice of quoting inflated output power figures by using a 10% distortion limit.
 

gfx_1

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The datasheet of the MA12070P mentions 2x40W but the graphs show 10W max before the distortion starts to rise.
Peak power could be achived by large capacitors but my guess is that 3x 1uF doesn't do that.
 
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